You say D joke when ever some one says a stupid joke. This is usually said by kids at Ching Secondary school. This word was made up by a group of kids because a student named Darion always makes dumb jokes.

3- Originating from the slums of Parkdale, this work was first mouthed by mixed Afro-Canadians while playing hockey in their backyard rinks.
JUST HYPOTHESIS, scientists have yet to confirm the exact origin of this word.